POJ 2823 Sliding Window
Sliding Window
| Time Limit: 12000MS | Memory Limit: 65536K | |
| Total Submissions: 26178 | Accepted: 7738 | |
| Case Time Limit: 5000MS | ||
Description
An array of size
n ≤ 10
6 is given to you. There is a sliding window of size
k which is moving from the very left of the array to the very right. You can only see the
k numbers in the window. Each time the sliding window moves rightwards by one position. Following is an example:
The array is [1 3 -1 -3 5 3 6 7], and kis 3.
The array is [1 3 -1 -3 5 3 6 7], and kis 3.
| Window position | Minimum value | Maximum value |
|---|---|---|
| [1 3 -1] -3 5 3 6 7 | -1 | 3 |
| 1 [3 -1 -3] 5 3 6 7 | -3 | 3 |
| 1 3 [-1 -3 5] 3 6 7 | -3 | 5 |
| 1 3 -1 [-3 5 3] 6 7 | -3 | 5 |
| 1 3 -1 -3 [5 3 6] 7 | 3 | 6 |
| 1 3 -1 -3 5 [3 6 7] | 3 | 7 |
Your task is to determine the maximum and minimum values in the sliding window at each position.
Input
The input consists of two lines. The first line contains two integers
n and
k which are the lengths of the array and the sliding window. There are
n integers in the second line.
Output
There are two lines in the output. The first line gives the minimum values in the window at each position, from left to right, respectively. The second line gives the maximum values.
Sample Input
8 3 1 3 -1 -3 5 3 6 7
Sample Output
-1 -3 -3 -3 3 3 3 3 5 5 6 7
Source
POJ Monthly--2006.04.28, Ikki
//开始有线段树做 9188MS
//后面改用刘老师的基础数据结构里面介绍的用单调队列做 5313MS
//不过用线段树写的不止简洁一丁点、
//也有可能是偶代码技术还不好
#include <iostream> #include <stdio.h> #include <string.h> #include <algorithm> #include <queue> #include <cmath> #define N 1000004 #define lson l,m,k<<1 #define rson m+1,r,k<<1|1 using namespace std; struct node { int min,max; }; node st[N<<2]; void build(int l,int r,int k) { if(l==r) { scanf("%d",&st[k].min); st[k].max=st[k].min; return ; } int m=(l+r)>>1; build(lson); build(rson); st[k].max=max(st[k<<1].max,st[k<<1|1].max); st[k].min=min(st[k<<1].min,st[k<<1|1].min); } int quMin(int &L,int &R,int l,int r,int k) { if(L<=l&&R>=r) { return st[k].min; } int m=(l+r)>>1; int t1=1000000000,t2=1000000000; if(L<=m) t1=quMin(L,R,lson); if(R>m) t2=quMin(L,R,rson); return t1<t2?t1:t2; } int quMax(int &L,int &R,int l,int r,int k) { if(L<=l&&R>=r) { return st[k].max; } int m=(l+r)>>1; int t1=-1000000000,t2=-1000000000; if(L<=m) t1=quMax(L,R,lson); if(R>m) t2=quMax(L,R,rson); return t1>t2?t1:t2; } int main() { int i,k; int n,m,r; while(scanf("%d%d",&n,&k)!=EOF) { build(1,n,1); m=n-k; for(i=1;i<=m;i++) r=i+k-1,printf("%d ",quMin(i,r,1,n,1)); r=m+1; printf("%d\n",quMin(r,n,1,n,1)); for(i=1;i<=m;i++) r=i+k-1,printf("%d ",quMax(i,r,1,n,1)); r=m+1; printf("%d\n",quMax(r,n,1,n,1)); } return 0; }
#include <iostream> #include <stdio.h> #include <string.h> #include <algorithm> #include <queue> #include <cmath> #define N 1000004 using namespace std; struct node { int id,val; }; node M[N]; int front,back; int a[N]; int main() { int n,k,i; while(scanf("%d%d",&n,&k)!=EOF) { front=back=1; scanf("%d",&a[1]); M[front].val=a[1];M[front].id=1; for(i=2;i<=k;i++) { scanf("%d",&a[i]); if(a[i]<=M[back].val) { while(1) { M[back].val=a[i],M[back].id=i; if(back>front&&a[i]<=M[back-1].val) back--; else break; } } else { M[++back].val=a[i]; M[back].id=i; } } printf("%d",M[front].val); for(i=k+1;i<=n;i++) { scanf("%d",&a[i]); if(a[i]<=M[back].val) { while(1) { M[back].val=a[i],M[back].id=i; if(back>front&&a[i]<=M[back-1].val) back--; else break; } } else { M[++back].val=a[i]; M[back].id=i; } while(M[front].id<i-k+1) front++; printf(" %d",M[front].val); } printf("\n"); front=back=1; M[front].val=a[1];M[front].id=1; for(i=2;i<=k;i++) { if(a[i]>=M[back].val) { while(1) { M[back].val=a[i],M[back].id=i; if(back>front&&a[i]>=M[back-1].val) back--; else break; } } else { M[++back].val=a[i]; M[back].id=i; } } printf("%d",M[front].val); for(i=k+1;i<=n;i++) { if(a[i]>=M[back].val) { while(1) { M[back].val=a[i],M[back].id=i; if(back>front&&a[i]>=M[back-1].val) back--; else break; } } else { M[++back].val=a[i]; M[back].id=i; } while(M[front].id<i-k+1) front++; printf(" %d",M[front].val); } printf("\n"); } return 0; }